1. Field of the Invention
The present invention relates to an apparatus and a method for connection control in a telecommunications network system, and more particularly to such an apparatus and a method applicable to, for example, a SIP (Session Initiation Protocol) signal converter provided on the boundary between different IP (Internet Protocol) networks and adapted to convert SDPs (Session Description Protocols).
2. Description of the Background Art
Recently, attempts are made to provide various communications services, such as speech, video (still and moving pictures) data and those collaborative with each other. In order to assure interconnections between endpoints participating in such communications services, the SIP is utilized.
For example, Japanese Patent Laid-Open Publication Nos. 2005-198181 and 2006-5754 disclose solutions for a SIP signal converter, which is, specifically, cooperative with a NAT (Network Address Translation) system to translate IP addresses and port numbers in SDPs.
However, the conventional solutions suffer from the problem that, in the IP-based communications of, for example, speech or video, if media formats usable on opposite endpoints differ from each other, then media negotiation for media format conversion in terms of establishing an interconnection between the endpoints is not possible.